<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>留言板</title>
  <style>
    .container {
      width: 350px;
      height: 300px;
      margin: 0 auto;
      /* border: 1px black solid; */
      text-align: center;
    }

    .grey {
      color: grey;
    }

    .container .row {
      width: 350px;
      height: 40px;

      display: flex;
      justify-content: space-between;
      align-items: center;
    }

    .container .row input {
      width: 260px;
      height: 30px;
    }

    #submit {
      width: 350px;
      height: 40px;
      background-color: orange;
      color: white;
      border: none;
      margin: 10px;
      border-radius: 5px;
      font-size: 20px;
    }
  </style>
</head>

<body>
<div class="container">
  <h1>留言板</h1>
  <p class="grey">输入后点击提交, 会将信息显示下方空白处</p>
  <div class="row">
    <span>谁:</span> <input type="text" name="" id="from">
  </div>
  <div class="row">
    <span>对谁:</span> <input type="text" name="" id="to">
  </div>
  <div class="row">
    <span>说什么:</span> <input type="text" name="" id="say">
  </div>
  <input type="button" value="提交" id="submit" onclick="submit()">
  <!-- <div>A 对 B 说: hello</div> -->
</div>

<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.4/jquery.min.js"></script>
<script>
  $.ajax({
    url: "/message/getList",
    type: "get",
    success: function (messageInfos) {
      var finalHtml = "";
      for (var message of messageInfos) {
        finalHtml += '<div>' + message.from + ' 对 ' + message.to + ' 说: ' + message.say + '</div>';
      }
      $(".container").append(finalHtml);
    }
  });

  function submit() {
    //1. 获取留言的内容
    var from = $('#from').val();
    var to = $('#to').val();
    var say = $('#say').val();
    //参数校验
    if (from == '' || to == '' || say == '') {
      return;
    }
    //发送ajax请求
    $.ajax({
      url: "/message/publish",
      type: "post",
      data: {
        //不好理解
        // from: from,
        // to: to,
        // say: say
        from: $('#from').val(),
        to: $('#to').val(),
        say:$('#say').val()
      },
      success: function (result) {
        if (result) {
          //2. 构造节点
          var divE = "<div>" + from + "对" + to + "说:" + say + "</div>";
          //3. 把节点添加到页面上
          $(".container").append(divE);
          //4. 清空输入框的值
          $('#from').val("");
          $('#to').val("");
          $('#say').val("");
        } else{
          alert("输入不合法");
        }
      }
    });
  }

</script>
</body>

</html>